%0 Journal Article
%T Flight Control Design for a Tailless Aircraft Using Eigenstructure Assignment
%A Clara Nieto-Wire
%A Kenneth Sobel
%J International Journal of Aerospace Engineering
%D 2011
%I Hindawi Publishing Corporation
%R 10.1155/2011/549131
%X We apply eigenstructure assignment to the design of a flight control system for a wind tunnel model of a tailless aircraft. The aircraft, known as the innovative control effectors (ICEs) aircraft, has unconventional control surfaces plus pitch and yaw thrust vectoring. We linearize the aircraft in straight and level flight at an altitude of 15,000 feet and Mach number 0.4. Then, we separately design flight control systems for the longitudinal and lateral dynamics. We use a control allocation scheme with weights so that the lateral pseudoinputs are yaw and roll moment, and the longitudinal pseudoinput is pitching moment. In contrast to previous eigenstructure assignment designs for the ICE aircraft, we consider the phugoid mode, thrust vectoring, and stability margins. We show how to simultaneously stabilize the phugoid mode, satisfy MIL-F-8785C mode specifications, and satisfy MIL-F-9490D phase and gain margin specifications. We also use a cstar command system that is preferable to earlier pitch-rate command systems. Finally, we present simulation results of the combined longitudinal/lateral flight control system using a full 6DOF nonlinear simulation with approximately 20,000 values for the aerodynamic coefficients. Our simulation includes limiters on actuator deflections, deflection rates, and control system integrators. 1. Introduction We consider the design of a flight control system using eigenstructure assignment for a wind tunnel model of the innovative control effectors (ICEs) aircraft. This tailless aircraft program was first described by Dorsett and Mehl [1] and by Dorsett et al. [2]. The ICE aircraft has many unconventional control surfaces plus pitch and yaw thrust vectoring. Several authors have proposed flight control system designs for the ICE aircraft. Ngo et al. [3] use dynamic inversion with structured singular value synthesis. However, the authors remove the bank angle equation from the model which causes an unstable complex mode to be replaced with an unstable real mode. This occurs because the ICE aircraft does not exhibit the conventional real spiral mode. Sparks [4] uses linear parameter-varying control. Schumacher and Johnson [5] use dynamic inversion with adaptation for self reconfiguring. Shtessel et al. [6] propose reconfigurable sliding mode control with direct adaptation. Hess et al. [7] use sliding mode control with asymptotic observers. However, the results are based only upon linear simulation. The only previous design using eigenstructure assignment was proposed by Jones et al. [8]. The main emphasis of [8] is a method
%U http://www.hindawi.com/journals/ijae/2011/549131/